ADP2109

ADP2109 (Rev. B) - OBSOLETE

Document overview

• Manufacturer or author: Analog Devices, Inc.
• PDF pages: 16

Technical content

Compact 600 mA, 3 MHz, Step-Down Converter with Output Discharge Data Sheet ADP2109 Rev. B Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2009–2012 Analog Devices, Inc. All rights reserved.

FEATURES

Peak efficiency: 95% Discharge switch function Fixed frequency operation: 3 MHz Typical quiescent current: 18 μA Maximum load current: 600 mA Input voltage: 2.3 V to 5.5 V Uses tiny multilayer inductors and capacitors Current mode architecture for fast load and line transient response 100% duty-cycle low dropout mode Internal synchronous rectifier Internal compensation Internal soft start Current overload protection Thermal shutdown protection Shutdown supply current: 0.2 μA 5-ball WLCSP Supported by ADIsimPower™ design tool

APPLICATIONS

PDAs and palmtop computers Wireless handsets Digital audio, portable media players Digital cameras, GPS navigation units GENERAL DESCRIPTION The ADP2109 is a high efficiency, low quiescent current step- down dc-to-dc converter with an internal discharge switch that allows automatic discharge of the output capacitor in an ultra- small 5-ball WLCSP package. The total solution requires only three tiny external components. It uses a proprietary high speed current mode and constant frequency pulse-width modulation (PWM) control scheme for excellent stability, and transient response. To ensure the longest battery life in portable applications, the ADP2109 has a power save mode that reduces the switching frequency under light load conditions. The ADP2109 runs on input voltages of 2.3 V to 5.5 V, which allow for single lithium or lithium polymer cell, multiple alkaline or NiMH cells, PCMCIA, USB, and other standard power sources. The maximum load current of 600 mA is achievable across the input voltage range. The ADP2109 is available in fixed output voltages of 1.8 V, 1.5 V, 1.2 V , and 1.0 V. All versions include an internal power switch and synchronous rectifier for minimal external part count and high efficiency. The ADP2109 has an internal soft start and internal compensation. During logic-controlled shutdown, the input is disconnected from the output and the ADP2109 draws less than 1 μA from the input source. Other key features include undervoltage lockout to prevent deep battery discharge and soft start to prevent input current overshoot at startup. The ADP2109 is available in a 5-ball WLCSP. A similar converter, the ADP2108, provides the same features and operations as the ADP2109 without the discharge switch and is available in both WLCSP and TSOT packages with additional output voltages. TYPICAL APPLICATIONS CIRCUIT 07964-001 1.0V TO 1.8V 10µF 1µH 4.7µF 2.3V TO 5.5V ON OFF ADP2109 GND VIN EN SW FB Figure 1. OBSOLETE

Rev. B | Page 2 of 16 TABLE OF CONTENTS Input and Output Capacitor, Recommended Specifications .. 3

REVISION HISTORY

7/12—Rev. A to Rev B 4/10—Rev. 0 to Rev. A 4/09—Revision 0: Initial Version OBSOLETE

Rev. B | Page 3 of 16 SPECIFICATIONS VIN = 3.6 V, VOUT = 1.8 V, TJ = −40°C to +125°C for minimum/maximum specifications, and TA = 25°C for typical specifications, unless otherwise noted.1 Table 1. Parameters Conditions Min Typ Max Unit INPUT CHARACTERISTICS Input Voltage Range 2.3 5.5 V Undervoltage Lockout Threshold VIN rising 2.3 V VIN falling 2.05 2.15 2.25 V OUTPUT CHARACTERISTICS Output Voltage Accuracy PWM mode −2 +2 % VIN = 2.3 V to 5.5 V, PWM mode −2.5 +2.5 % POWER SAVE MODE TO PWM CURRENT THRESHOLD 85 mA PWM TO POWER SAVE MODE CURRENT THRESHOLD 80 mA INPUT CURRENT CHARACTERISTICS DC Operating Current ILOAD = 0 mA, device not switching 18 30 μA Shutdown Current EN = 0 V, TA = TJ = −40°C to +85°C 0.2 1.0 μA SW CHARACTERISTICS SW On Resistance PFET 320 mΩ NFET 300 mΩ Current Limit PFET switch peak current limit 1100 1300 1500 mA Discharge SW Resistance VOUT = 1.0 V 150 Ω ENABLE CHARACTERISTICS EN Input High Threshold 1.2 V EN Input Low Threshold 0.4 V EN Input Leakage Current EN = 0 V, 3.6 V −1 0 +1 μA OSCILLATOR FREQUENCY ILOAD = 200 mA 2.5 3.0 3.5 MHz START-UP TIME 550 μs THERMAL CHARACTERISTICS Thermal Shutdown Threshold 150 °C Thermal Shutdown Hysteresis 20 °C 1 All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC). INPUT AND OUTPUT CAPACITOR, RECOMMENDED SPECIFICATIONS Table 2. Parameter Symbol Conditions Min Typ Max Unit MINIMUM INPUT AND OUTPUT CAPACITANCE CMIN TA = −40°C to +125°C 4.7 µF MINIMUM AND MAXIMUM INDUCTANCE L TA = −40°C to +125°C 0.3 3.0 µH OBSOLETE

θJA is specified for a device mounted on a JEDEC 2S2P PCB. Table 4. Thermal Resistance

Figure 2. Pin Configuration Table 5. Pin Function Descriptions capacitor as close to the ADP2109 as possible. A2 GND Ground. Connect all the input and output capacitors to GND. B SW Switch Node Output. SW is the drain of the PFET switch and NFET synchronous rectifier. C1 EN Enable Input. Drive EN high to turn on the ADP2109. Drive EN low to turn it off and reduce the input current to 0.1 μA. C2 FB Feedback Input of the Error Amplifier. Connect FB to the output of the switching regulator.

Figure 26. Functional Block Diagram for a small step-down dc-to-dc converter solution. regulates an output voltage down to 1.0 V. integrated switches is adjusted and regulates the output voltage. the inductor to make VOUT rise again to the upper threshold. save mode current threshold.

Figure 27. Internal Discharge Switch on Feedback quency is reduced to half of the internal oscillator frequency. tion, poor circuit board design, and/or high ambient temperature. of thermal shutdown, soft start is initiated. connected to the input of the converter. consists of the power-up time and soft start time.

The ADP2109 is supported by ADIsimPower design tool set. unpopulated board through the tool. the applications circuit, as shown in Figure 1. inductors are shown in Table 6. fSW is the switching frequency. through the inductor, which has an associated internal DCR. Table 6. Suggested 1.0 μH Inductors poor temperature and dc bias characteristics. CEFF is the effective capacitance at the operating voltage. TEMPCO is the worst-case capacitor temperature coefficient. TOL is the worst-case component tolerance. over −40°C to +85°C is assumed to be 15% for an X5R dielectric. COUT is 9.2481 μF at 1.8 V from the graph in Figure 28. behavior of the capacitors be evaluated for each application. Figure 28. Typical Capacitor Performance

temperature and dc bias effects, i s 7 µF. Table 7. Suggested 10 μF Capacitors ripple and improve transient response. capacitor, a low ESR capacitor is recommended. The list of recommended capacitors is shown in Table 8. Table 8. Suggested 4.7 μF Capacitors which reduces thermal constraints. when the junction temperature falls below 130°C. TJ is the junction temperature. TA is the ambient temperature. TR is the rise of temperature of the package. ambient temperature of the package. PD is the power dissipation in the package. losses. Poor layout can also affect regulation and stability.

• Place the inductor, input capacitor, and output capacitor close to the IC using short tracks. These components carry high switching frequencies and the large tracks act like antennas.
• Route the output voltage path away from the inductor and SW node to minimize noise and magnetic interference.
• Maximize the size of ground metal on the component side to help with thermal dissipation.
• Use a ground plane with several vias connecting to the component side ground to further reduce noise interfe- rence on sensitive circuit nodes. OBSOLETE

Figure 32. 5-Ball Wafer Level Chip Scale Package [WLCSP]

Rev. B | Page 16 of 16 NOTES ©2009–2012 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D07964-0-7/12(B) OBSOLETE